The present invention relates to technology for controlling printing, particularly to technology effective by applying to controlling a printer, which has plural printing modes, for printing various printing information transmitted from a host computer.
In accordance with current change of information to increase variation and intellectual level, for instance, as described in "Nikkei Electronics" published by Nikkei BP Co. July 17, 1995, p 75.about.100, printers connected to computers have changed to be multifunctional, for instance, a printer capable of printing both color and monochromatic, and printing on both one plane and two planes has been practically used.
In using the multifunctional printer, conventionally, the printing mode of the printer has to be changed in accordance with printing information such as command/data, and the like, transmitted from the host computer. For instance, when printing sequence of color printing differs from that of monochromatic printing with the printer capable of both color printing and monochromatic printing, paper staying in the printer during printing operation must be removed once from the printer for changing the printing mode.
Therefore, the monochromatic printing and the color printing could not be performed continuously, and a technical problem, such as decreasing the printing efficiency by stopping the printing operation when changing the monochromatic printing with the color printing, was remained. That means, when a total through-put (the number of printed papers per unit time) is decreased by changing the printing mode, there are some cases of not so effective if the printing operation is performed with the printing mode just as instructed from the host computer. For instance, if the printing is performed in accordance with the printing mode of each of the pages sequentially when monochromatic pages and color pages must be printed continuously alternating each from other per one page, the continuous printing becomes impossible and the time necessary for printing is increased, because the operations for changing the printing mode per page and for removing paper staying in the printer are necessary.
As a countermeasure for the above case, for instance, a method for improving the through-put by dividing the printing to a printer for solely monochromatic printing and another printer for solely color printing can be considered. However, another technical problem such as increasing printing cost more than its necessity is generated, because two printers, the one is for solely monochromatic printing and the other is for solely color printing, becomes necessary, and an extra operation for dividing the printing data is required.